Electronic device that determines an uplink pilot sequence, and method therefor

ABSTRACT

A method for an electronic device includes determining, based on indicating information of an uplink pilot sequence allocated by a base station, an uplink pilot sequence, transmitting the uplink pilot sequence, and determining a change in a geographical location of the electronic device. In a case that the geographical locations of the electronic device before and after changing correspond to different cell partitions, the uplink pilot sequence is updated based on the indicating information allocated by the base station, and the updated uplink pilot sequence corresponds to the cell partition corresponding to the geographical location of the electronic device after changing. The uplink pilot sequence is for the base station estimating a channel between the base station and the electronic device, and filtering based on the geographical location of the electronic device during the channel estimation, to obtain a channel estimation result matching the electronic device.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.15/327,585, filed Jan. 19, 2017, which is based on PCT filingPCT/CN2015/076277, filed Apr. 10, 2015, and claims priority to CN201410386345.5, filed Aug. 7, 2014, the entire contents of each areincorporated herein by reference.

FIELD OF THE INVENTION

The embodiments of the present disclosure generally relates to the fieldof wireless communication, and particularly to an apparatus and a methodfor wireless communication, an electronic device and a method for theelectronic device. More particularly, the embodiments of the presentdisclosure relate to pilot allocation and channel estimation techniquesin a massive Multiple Input Multiple Output (MIMO) communication system.

BACKGROUND OF THE INVENTION

A massive MIMO (massive MIMO) system has attracted wide attention inacademics and industry in recent years. The theoretical research showsthe massive MIMO system can significantly improve spectrum efficiencyand energy efficiency simultaneously by a simple linear algorithm suchas the zero-forcing algorithm, the minimum mean-square error algorithmand the like. Therefore, the massive MIMO system is likely to be adoptedas a key technique in the next-generation communication standard.

However, for example, performance of the massive MIMO system inmulti-cell time division multiplexing scenario is limited due to aproblem of pilot pollution. Specifically, since the length of a pilot islimited to a coherent length of a channel, the number of orthogonalpilots is limited, and it is inevitable that a pilot is reused amongdifferent cells. In this case, pilot signals transmitted by the users,located in different cells, which use a same pilot sequence or pilotsequences which are incomplete orthogonal may be received by a same basestation. However, the base station can not distinguish the pilot signalseffectively, and thus channel estimation at the base station isdisturbed. In a case that the base station adopts the disturbed channelestimation to detect uplink data, not only data transmitted by a user inthe present cell is received, but also data transmitted from a user inanother cell is received, which results in inter-cell interferences inthe uplink. In a case that the base station adopts the disturbed channelestimation to generate a pre-coding matrix and transmit downlink data,the downlink data can be received not only by the user in the presentcell, but also by the user in the another cell, which results ininter-cell interferences in the downlink interference.

The theoretical research shows that, although both the spectrumefficiency and energy efficiency of the massive MIMO system can beimproved significantly, and an influence of the noise and a channelestimation error on the performance of the massive MIMO system isbecoming smaller with the increase of the number of antennas in the basestation, the inter-cell interferences caused by the pilot pollution cannot be eliminated, which becomes one of limiting factors for theperformance of the massive MIMO system.

The existing methods for alleviating the pilot pollution are difficultto be applied considering the current technical condition, andtherefore, the pilot pollution is still one of the serious problems ofthe massive MIMO system in the actual application. In addition, thepilot pollution becomes worse with the continuous increase of the numberof the users within the cell.

SUMMARY OF THE INVENTION

In the following, an overview of the present invention is given simplyto provide basic understanding to some aspects of the present invention.It should be understood that this overview is not an exhaustive overviewof the present invention. It is not intended to determine a criticalpart or an important part of the present invention, nor to limit thescope of the present invention. An object of the overview is only togive some concepts in a simplified manner, which serves as a preface ofa more detailed description described later.

An apparatus for wireless communication is provided according to anaspect of the present disclosure, which includes: a location determiningunit, configured to determine a cell partition corresponding to ageographical location of a communication device, each cell includingmultiple cell partitions; and a pilot determining unit, configured todetermine an uplink pilot sequence corresponding to the cell partitionas an uplink pilot sequence of the communication device.

A method for wireless communication is provided according to anotheraspect of the present disclosure, which includes: determining a cellpartition corresponding to a to geographical location of a communicationdevice, each cell including multiple cell partitions; and determining anuplink pilot sequence corresponding to the cell partition as an uplinkpilot sequence of the communication device.

An apparatus for wireless communication is further provided according toa further aspect of the present disclosure, which includes: a dividingunit, configured to divide each cell of multiple cells into multiplecell partitions; and a pilot pattern generating unit, configured tocorrespond multiple uplink pilot sequences with the cell partitions togenerate a pilot pattern, where the pilot pattern is generated based onpilot interferences between different cell partitions which arecorresponding to a same uplink pilot sequence.

A method for wireless communication is provided according to anotheraspect of the present disclosure, which includes: dividing each cell ofmultiple cells into multiple cell partitions; and corresponding multipleuplink pilot sequences with the cell partitions to generate a pilotpattern, where the pilot pattern is generated based on pilotinterferences between different cell partitions which are correspondingto a same uplink pilot sequence.

An electronic device is provided according to another aspect of thepresent disclosure, which includes: an uplink pilot sequence determiningunit, configured to determine, based on indicating information of anuplink pilot sequence allocated by a base station, an uplink pilotsequence of the electronic device; and a location determining unit,configured to determine a change in a geographical location of theelectronic device, where in a case that the geographical locations ofthe electronic device before and after changing correspond to differentcell partitions, the uplink pilot sequence determining unit updates,based on the indicating information of the uplink pilot sequenceallocated by the base station, the uplink pilot sequence of theelectronic device, the updated uplink pilot sequence being correspondingto the cell partition corresponding to the geographical location of theelectronic device after changing.

A method for an electronic device is provided according to anotheraspect of the present disclosure, which includes: determining, based onindicating information of an uplink pilot sequence allocated by a basestation, an uplink pilot sequence of the electronic device; anddetermining a change in a geographical location of the electronicdevice, where in a case that the geographical locations of theelectronic device before and after changing correspond to different cellpartitions, the uplink pilot sequence of the electronic device isupdated based on the indicating information of the uplink pilot sequenceallocated by the base station, the updated uplink pilot sequence beingcorresponding to the cell partition corresponding to the geographicallocation of the electronic device after changing.

An apparatus for wireless communication is provided according to anotheraspect of the present disclosure, which includes: a pilot determiningunit, configured to determine a first uplink pilot sequence for a firstcommunication device; and a channel estimation unit, configured toperform, based on a received signal carrying the first uplink pilotsequence, channel estimation on the first communication device, wherethe channel estimation unit performs, based on a geographical locationof the first communication device, filtering during the channelestimation, to obtain a channel estimation result matching the firstcommunication device.

A method for wireless communication is provided according to an aspectof the present disclosure, which includes: determining a first uplinkpilot sequence for a first communication device; and performing, basedon a received signal carrying the first uplink pilot sequence, channelestimation on the first communication device, where filtering isperformed during the channel estimation based on a geographical locationof the first communication device, to obtain a channel estimation resultmatching the first communication device.

Computer program codes and a computer program product for implementingthe method for wireless communication and the method for the electronicdevice described above, and a computer-readable storage medium on whichthe computer program codes for implementing the method for wirelesscommunication and the method for the electronic device described aboveare recorded are further provided according to other aspects of thepresent disclosure.

In the apparatus and method for wireless communication according to thepresent disclosure, the uplink pilot sequence is allocated and thechannel estimation is performed based on the location of thecommunication device, thereby significantly reducing inter-interferencescaused by pilot pollution, and improving overall performance of thesystem. In addition, spatial multiplexing for the uplink pilot sequencescan be realized by the apparatus and the method for the wirelesscommunication according to the present disclosure. A same uplink pilotsequence or a correlated uplink pilot sequence can be used even forcommunication devices in a same cell, thereby increasing the number ofcommunication devices which can be supported.

These and other advantages of the present invention will be moreapparent by illustrating in detail a preferred embodiment of the presentinvention in conjunction with accompanying drawings below.

BRIEF DESCRIPTION OF THE DRAWINGS

To further set forth the above and other advantages and features of thepresent invention, detailed description will be made in the followingtaken in conjunction with accompanying drawings in which identical orlike reference signs designate identical or like components. Theaccompanying drawings, together with the detailed description below, areincorporated into and form a part of the specification. It should benoted that the accompanying drawings only illustrate, by way of example,typical embodiments of the present invention and should not be construedas a limitation to the scope of the invention. In the accompanyingdrawings:

FIG. 1 is a structural block diagram showing an apparatus for wirelesscommunication according to an embodiment of the present disclosure:

FIG. 2 is a schematic diagram showing an example of a two-dimensionalantenna array.

FIG. 3 is a structural block diagram showing an apparatus for wirelesscommunication according to another embodiment of the present disclosure;

FIG. 4 is a structural block diagram showing an apparatus for wirelesscommunication according to another embodiment of the present disclosure;

FIG. 5 is a structural block diagram showing a channel estimation moduleaccording to an embodiment of the present disclosure;

FIG. 6 shows an example of a pilot pattern according to an embodiment ofthe present disclosure;

FIG. 7 shows a possible pilot pattern in a single-cell heterogeneousnetwork;

FIG. 8 is a flowchart showing a method for wireless communicationaccording to an embodiment of the present disclosure;

FIG. 9 is a flowchart showing sub steps of a step of channel estimationin the method in FIG. 8;

FIG. 10 is a structural block diagram showing an apparatus for wirelesscommunication according to another embodiment of the present disclosure;

FIG. 11 shows an example of cell partition for a cell, an access pointof which adopts a one-dimensional evenly spaced linear antenna array;

FIG. 12 shows an example of cell partition for a cell, an access pointof which adopts a two-dimensional antenna array;

FIG. 13 is a graph showing a mean-square error of channel estimationaccording to a simulation example;

FIG. 14 is a graph showing an uplink capacity according to a simulationexample;

FIG. 15 is a graph showing a downlink capacity according to a simulationexample;

FIG. 16 is a structural block diagram showing an apparatus for wirelesscommunication according to another embodiment of the present disclosure;

FIG. 17 is a flowchart showing a method for wireless communicationaccording to another embodiment of the present disclosure;

FIG. 18 is a structural block diagram showing an electronic deviceaccording to an embodiment of the present disclosure;

FIG. 19 is a structural block diagram showing an electronic deviceaccording to another embodiment of the present disclosure;

FIG. 20 is a structural block diagram showing a method for an electronicdevice according to an embodiment of the present disclosure;

FIG. 21 is a structural block diagram showing an apparatus for wirelesscommunication according to another embodiment of the present disclosure;

FIG. 22 is a structural block diagram showing an example of a spatialfiltering module according to an embodiment of the present disclosure;

FIG. 23 is a structural block diagram showing an example of a channelestimation unit according to an embodiment of the present disclosure;

FIG. 24 is a flowchart showing a method for wireless communicationaccording to another embodiment of the present disclosure;

FIG. 25 is a flowchart showing sub steps of an example of step S62 inFIG. 24;

FIG. 26 is a structural block diagram showing an apparatus for wirelesscommunication according to another embodiment of the present disclosure;

FIG. 27 is a flowchart showing a method for wireless communicationaccording to another embodiment of the present disclosure: and

FIG. 28 is an exemplary block diagram illustrating the structure of ageneral purpose personal computer capable of realizing the method and/ordevice and/or system according to the embodiments of the presentinvention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

An exemplary embodiment of the present invention will be describedhereinafter in conjunction with the accompanying drawings. For thepurpose of conciseness and clarity, not all features of an embodimentare described in this specification. However, it should be understoodthat multiple decisions specific to the embodiment have to be made in aprocess of developing any such embodiment to realize a particular objectof a developer, for example, conforming to those constraints related toa system and a business, and these constraints may change as theembodiments differs. Furthermore, it should also be understood thatalthough the development work may be very complicated andtime-consuming, for those skilled in the art benefiting from the presentdisclosure, such development work is only a routine task.

Here, it should also be noted that in order to avoid obscuring thepresent invention due to unnecessary details, only a device structureand/or processing steps closely related to the solution according to thepresent invention are illustrated in the accompanying drawing, and otherdetails having little relationship to the present invention are omitted.

First Embodiment

FIG. 1 shows a structural block diagram of an apparatus 100 for wirelesscommunication according to an embodiment of the present disclosure. Theapparatus 100 includes: a location determining unit 101, configured todetermine a cell partition corresponding to a geographical location of acommunication device, each cell including multiple cell partitions; anda pilot determining unit 102, configured to determine an uplink pilotsequence corresponding to the cell partition as an uplink pilot sequenceof the communication device.

Specifically, the apparatus 100 is configured to for example allocate anuplink pilot sequence for a communication device, so that thecommunication device can perform uplink data transmission using theallocated uplink pilot sequence. The apparatus 100 may be applied in forexample an MIMO communication system. As an example, the apparatus 100may be located at each access point or on a base station side, and isconfigured to determine the uplink pilot sequence for the communicationdevice within its service range. In general, a communication link from aservice node to the communication device is referred to as a downlink,and a communication link from the communication device to the servicenode is referred to as an uplink. As described in the example above, theservice node in the present disclosure is configured to allocate a pilotsequence to a user equipment, the pilot sequence being transmitted tothe service node from the user equipment. Specifically, the pilotdetermining unit 102 may determine multiple uplink pilot sequences, i.e.a group of uplink pilot sequences, and the uplink pilot sequences in thegroup are orthogonal to each other.

The communication device described here may be a user equipment such asa mobile terminal, a vehicle, an intelligent wearable device an so on.It should be noted that the communication device in the presentdisclosure may also be an infrastructure for providing a service, suchas a small cell base station. In a case that the communication device isthe small cell base station, the apparatus 100 for example located in amacro base station determines a pilot sequence for the small cell basestation as described above. Here, for example, a communication link fromthe macro base station to the small cell base station is regarded as adownlink in the present disclosure, and a communication link from thesmall cell base station to the macro base station is regarded as anuplink. In other words, the present disclosure is not limited tocommunication entities corresponding to a traditional uplink and atraditional downlink. In a case that a first communication device is todetermine a channel state from a second communication device within asignal coverage range thereof to the first communication device so as toallocate a pilot to the second communication device, the presentdisclosure is applied considering that the communication link from thesecond communication device to the first communication device is theuplink.

In the embodiment, each cell is divided into multiple cell partitions.The cell partition here may be a traditional sector partition, or may bea partition, which is different in shape and divided according toanother principle. The specific dividing manner will be described indetail later.

The location determining unit 101 determines a cell partition where ageographical location of the communication device is located, andprovides information on the cell partition to the pilot determining unit102, so that the pilot determining unit 102 can determine an uplinkpilot sequence corresponding to the cell partition as an uplink pilotsequence to be used by the communication device.

In the embodiment, after the location determining unit 101 determinesthat the geographical location of the communication device changes intoanother cell partition, the pilot determining unit 102 determines anuplink pilot sequence corresponding to the changed cell partition as theuplink pilot sequence of the communication device. In other words, theapparatus 100 can determine the uplink pilot sequence for thecommunication device dynamically. Specifically, the location determiningunit 101 may determine the geographical location of the communicationdevice periodically to determine whether the geographical locationchanges into another cell partition. Alternatively, the locationdetermining unit 101 may perform the determination in a case that achange in the geographical location of the communication device exceedsa certain extent. In some examples, the location determining unit 101detects the geographical location of the communication device activelyto perform the determination. In other examples, the locationdetermining unit 101 determines the geographical location of thecommunication device by a geographical location report from thecommunication device for example.

Specifically, the geographical location of the communication device canbe characterized by at least one of: an angle of arrival direction ofthe communication device; an angle of arrival direction and a distancefrom the communication device to the apparatus 100; geographicalcoordinates/geodetic coordinates such as longitude and latitude of thecommunication device; and an ID of a small cell where the communicationdevice is located. Specifically, for example, in a case that thelocation determining unit 101 detects the geographical location of thecommunication device actively, the geographical location of thecommunication device may be characterized by for example the angle ofarrival direction or the angle of arrival direction and the distancefrom the communication device to the apparatus 100. For example, in acase that the location determining unit 101 determines based on thegeographical location report of the communication device, thegeographical location of the communication device can be characterizedby for example the longitude and latitude of the communication device orthe ID of the small cell where the communication device is located.

In an actual communication system, a one-dimensional evenly spacedlinear antenna array or a two-dimensional antenna array can be used byan access point. FIG. 2 shows an example of the two-dimensional antennaarray, in which, a black spot represents an arranged antenna, D₁ and D₂represent the antenna interval in a horizontal direction and in avertical direction, respectively, and a solid line with an arrowrepresents a direction for receiving a signal as an example. FIG. 2 onlyshows nine antennas, however, it is only exemplary, and the size of theantennas is not limited thereto. In addition, in a case thatone-dimensional array is used, antennas on the y-axis can just be used.

Specifically, angle θ is an angle of arrival in the horizontaldirection, and angle β is an angle of arrival in the vertical direction.Since that the height of the antenna is known, the angle β can alsoreflect a distance from the communication device to the apparatus 100.In an example of the present disclosure, the two-dimensional antennaarray is configured for the access point. The location determining unit100 provided at the access point side determines an angle θ of arrivalin the horizontal direction and an angle β of arrival in the verticaldirection of a signal received from the communication device, anddetermines and characterizes the geographical location (includinginformation on the direction and the distance) of the communicationdevice based on the angle θ of arrival in the horizontal direction andthe angle β of arrival in the vertical direction. In another example ofthe present disclosure, the one-dimensional antenna array is configuredfor the access point. The location determining unit 101 provided at theaccess point side determines an angle θ of arrival in the horizontaldirection of a signal received from the communication device, anddetermines and characterizes the geographical location (includinginformation on a direction) of the communication device based on theangle θ of arrival in the horizontal direction. In addition, the accesspoint provided with the one-dimensional antenna array can furtherestimate, based on timing advance of the communication device or pathloss of the signal and the like, a distance from the communicationdevice to the access point, and characterize the geographical locationof the communication device according to the angle θ and the estimateddistance.

In addition, for example, in a case that the geographical location ofthe communication device is determined based on the geographicallocation report of the communication device, the geographical locationof the communication device can also be represented by the geodeticcoordinates such as longitude and latitude or the ID of the small cellwhere the communication device is located. Specifically, thecommunication device for example reports information on the longitudeand latitude determined by a GPS module thereof to the apparatus 100,for use by the location determining unit 101 to determine. In addition,for example, the access point where the apparatus 100 is located is amacro base station, and information on small cells having a relativelysmall coverage range deployed within a coverage range of the macro basestation is known in advance to the macro base station or can be queriedfor example via a database by the macro base station. In this case, anID of the small cell may reflect the geographical location of the smallcell within the range of the macro cell. In a case that thecommunication device is located within the coverage range of the smallcell, the communication device can receive the ID of the small cellbroadcasted by the small cell, and feed back the ID of the small cell tothe macro cell. The location determining unit 101 can acquire thelocation of the communication device based on the ID of the small celland deployment information of the small cell known to the macro cell inadvance or by querying the database. In a case that the apparatus 100 islocated outside of the macro base station, the apparatus 100 can alsoacquire the location of the communication device from the macro cell viaa communication interface with the macro base station.

Second Embodiment

FIG. 3 is a structural block diagram showing an apparatus 200 forwireless communication according to another embodiment of the presentdisclosure. In addition to components the same as those in FIG. 1, theapparatus 200 further includes: a receiving unit 201, configured toreceive information indicating the geographical location transmitted bythe communication device; and a transmitting unit 202, configured totransmit indicating information of the uplink pilot sequence to thecommunication device via a dedicated control signaling, to allocate theuplink pilot sequence to the communication device.

The information indicating the geographical location described here maybe explicit location information (for example GPS positioninginformation), or may be a normal signal implicitly reflecting thelocation information. The apparatus 200 may obtain information such asan angle of arrival direction, timing advance, path loss or the likebased on the normal signal, and deduce the geographical location of thecommunication device coarsely.

After the pilot determining unit 102 determines the uplink pilotsequence of the communication device, the transmitting unit 202transmits the indicating information corresponding to the uplink pilotsequence to the communication device. The communication devicedetermines the uplink pilot sequence to be used based on the receivedindicating information. The indicating information may be an indexrepresenting the uplink pilot sequence, or may be the uplink pilotsequence itself. As an example, the uplink pilot sequence may be areference sequence for a Sounding Reference Signal (SRS) or aDemodulation Reference Signal in the LTE standard.

Specifically, the transmitting unit 202 may transmit the indicatinginformation described above via the dedicated control signaling (ahigh-layer signaling) such as a radio resource control (RRC) signalingin the LTE standard. Specifically, for example, the indicatinginformation described above is included in the sounding reference signaluplink configuration information element (SoundingRS-UL-Config IE). Morespecifically, the indicating information is for example an SRSconfiguration index (SRS-ConfigIndex).

Alternatively, the communication device can also be notified of theuplink pilot sequence to be used in the following manner: a base station(or the apparatus 200) contains a geographical range of each cellpartition and an uplink pilot sequence corresponding to the cellpartition in broadcasting information, so as broadcast it to all users.Each of the users determines, based on a geographical location of itselfand the received broadcasting information, a cell partition where theuser is located and an uplink pilot sequence to be used. In this case,it is not necessary for the communication device to report itsgeographical location.

In addition, the receiving unit 201 may be further configured to receivepilot pattern information including a correspondence between each cellpartition and an uplink pilot sequence of the cell partition from acentral node. The pilot determining unit 102 is configured to determinean uplink pilot sequence of the communication device based on the pilotpattern information. In this case, the uplink pilot allocation for allcell partitions is managed uniformly by the central node. The receivingunit 201 can acquire the pilot pattern information from the central nodeperiodically, or renewedly acquire the pilot pattern information onlywhen the pilot pattern information is updated by the central node, oracquire the pilot pattern information in a combination of the two waysdescribed above. The central node provides pilot pattern information onmultiple cell partitions included in a cell for at least one cell.Preferably, the central node is a management device such as a server formanaging multiple cells, for example, a server on a core network side ora super controller (SRC)/Cloud BB (basic band) in an unbounded networksolution (for example, C-RAN). In another example, the receiving unit201 may be further configured to receive uplink pilot sequenceinformation of a cell partition of another cell adjacent to the cellpartition where the communication device is located. The pilotdetermining unit 102 is configured to determine, based on the uplinkpilot sequence information of the cell partition of another cell, theuplink pilot sequence corresponding to the cell partition where thecommunication device is located. Specifically, in a case that theapparatus is provided on the base station side, the receiving unit 201interchanges the uplink pilot sequence information corresponding to thecell partition with an adjacent base station via for example an X2interface. By taking the uplink pilot sequence information of the cellpartitions of adjacent cells into consideration, the adjacent cellpartitions can be prevented from using the same uplink pilot sequence asmuch as possible. By enabling adjacent cell partitions to correspond todifferent uplink pilot sequences, interferences caused by the pilotpollution can be reduced.

Third Embodiment

A structural block diagram of an apparatus 300 for wirelesscommunication according to another embodiment of the present disclosureis described below with reference to FIG. 4. In addition to componentsdescribed in FIG. 3, the apparatus 300 further include a channelestimation unit 301. In the embodiment, adjacent cell partitionscorrespond to different uplink pilot sequences.

The receiving unit 201 is further configured to receive a signalcarrying a first uplink pilot sequence, and the channel estimation unit301 is configured to perform, based on the signal carrying the firstuplink pilot sequence, channel estimation on a communication device towhich the first uplink pilot sequence is allocated. Specifically, thechannel estimation unit 301 performs, based on a geographical locationof the communication device to which the first uplink pilot sequence isallocated, filtering during the channel estimation, to obtain a channelestimation result matching the communication device.

Specifically, since communication devices served by the base station atthe same time and allocation of uplink pilot sequences among thecommunication devices are known to the base station, the base stationcan determine, based on the uplink pilot sequence information, whichcommunication device transmits the pilot by itself, and the channelestimation unit 301 may perform filtering based on the geographicallocation of the communication device. An objective of the filteringduring the channel estimation is to eliminate pollution from a samepilot transmitted by another communication device.

FIG. 5 is a structural block diagram showing an example of the channelestimation unit 301. The channel estimation unit 301 includes: a coarsechannel estimation module 3001, configured to perform, based on thesignal carrying the first uplink pilot sequence and the first uplinkpilot sequence, coarse estimation on channel coefficients; and a spatialfiltering module 3002, configured to perform, based on the geographicallocation of the communication device to which the first uplink pilotsequence is allocated, filtering on the coarse estimation for thechannel coefficients.

Specifically, various known estimation ways can be used by the coarsechannel estimation module 3001. Since the pilot determining unit 102determines different uplink pilot sequences for adjacent cellpartitions, different users which use the same pilot substantially wouldnot have a same location parameter such as an angle of arrival directionor a distance from the user to the base station or the like.Practically, in order to ensure that different users which use the samepilot would not have a same location parameter, location parameters ofdifferent users which use the same pilot can be set to be different byspecial design. An example is given below in conjunction with FIG. 6,where each hexagon represents a cell, each cell is divided into 12 cellpartitions, and each number labeled in each cell partition represents anindex of a pilot sequence allocated to the cell. For example, an indexof a pilot sequence of one cell partition within a cell 0 in the centeris 2. In a case that the location parameter is an angle of arrival inthe horizontal direction, and a range of the angle of arrival in thehorizontal direction of a part of cell partitions within the cell 1adjacent to the cell 0 is the same as that from the cell partition, theindex of which is 2, to the base station of the cell 0, an index of thepilot sequence corresponding to the part of cell partitions (a part orall of the part thereof) within the cell 1 described above can beassigned an index value except 2 by special design, to avoid userinterferences from another cell having the same location parameter.

In other words, the location parameter of the user within a specificcell partition is substantially limited within a certain range. Based onthis, the spatial filtering module 3001 performs spatial filtering basedon the geographical location of the communication device, therebysignificantly reducing a mean-square error of the channel estimation.

In an example, the spatial filtering module 3002 may be configured toperform filtering by performing discrete Fourier transform on the coarseestimation for the channel coefficients and windowing a result of thetransform.

An implementation of the coarse channel estimation module 3001 and thespatial filtering module 3002 is described below by a specific example.It should be understood that the implementation of the coarse channelestimation module 3001 and the spatial filtering module 3002 is notlimited to the following description.

First, the coarse channel estimation module 3001 multiplies the signalcarrying the first uplink pilot sequence with the first uplink pilotsequence, to obtain coarse estimation for the channel coefficients.Then, the spatial filtering module 3002 performs discrete Fouriertransform on the coarse estimation for the channel coefficients, appliesa rectangular window on a result of the transform, and finally performsinverse discrete Fourier transform on a signal obtained after applyingthe window, to obtain final estimation for the channel coefficient.

In an example, a one-dimensional evenly spaced linear antenna array isused for the access point, and the discrete Fourier transform performedis one-dimensional transform. A location of the rectangular window isdetermined based on a range of the angle of arrival direction of thecommunication device. For example, a minimum index k_(min) and a maximumindex k_(max) of the rectangular window are determined according toformula (I) as follows.

$\begin{matrix}\left\{ \begin{matrix}{k_{\min} = \left\lbrack {N - {N\frac{D}{\lambda}{\cos \left( \theta_{\min} \right)}}} \right\rbrack} \\{k_{\max} = \left\lbrack {N - {N\frac{D}{\lambda}{\cos \left( \theta_{\max} \right)}}} \right\rbrack}\end{matrix} \right. & (1)\end{matrix}$

where θ_(min) and θ_(max) are a minimum angle of arrival direction and amaximum angle of arrival direction (angle of arrival in the horizontaldirection) within a detection section, respectively, N is the number ofpoints involved in the discrete Fourier transform and is generallygreater than the number of antennas of the access point; D and λ are anantenna space and a wavelength of received signal, respectively, [ ]represents a rounding operation.

Alternatively, the discrete Fourier transform may be not performed, andthe coarse estimation for the channel coefficients is filtered directlyby a filter as follows.

$\begin{matrix}{{x(n)} = \left\{ \begin{matrix}{\frac{k_{\max} - k_{\min}}{N},} & {n = 0} \\{{\frac{1}{N}\frac{{\exp \left\{ {j\frac{2\; \pi \; k_{\min}}{N}n} \right\}} - {\exp \left\{ {j\frac{2\; \pi \; k_{\max}}{N}n} \right\}}}{1 - {\exp \left\{ {j\frac{2\; \pi \; n}{N}} \right\}}}},} & {{n = 1},\ldots \mspace{14mu},{N - 1}}\end{matrix} \right.} & (2)\end{matrix}$

Definition for each parameter is the same as definition of theparameters in formula (1). Correspondingly, linear convolution orcircular convolution may be used in the filtering process. In a casethat the circular convolution is used, the filtering process isdescribed as follows: 1) calculating a filter based on the detectionsection for the angle of arrival direction (as shown in formula (2)); 2)zero-padding a received signal to make the received signal have a samelength as the length N of the filter; 3) performing circular convolutionon the received zero-padded signal and the filter; 4) intercepting thefirst M components of a signal after the circular convolution as achannel estimation result assuming that the number of antennas is M. Ina case that the linear convolution is used, the filtering process isdescribed as follows: 1) calculating a filter based on a detectionsection for the angle of arrival direction (as shown in formula (2)): 2)performing linear convolution on a received signal and the filter; 3)assuming that the number of the antennas is M, a signal after theconvolution has N+M−1 components, superimposing the last (M−1)components on the first (M−1) components; 4) intercepting the first Mcomponents as a channel estimation result.

In another example, the evenly spaced two-dimensional antenna array isused for the access point (for example, as shown in FIG. 2), thediscrete Fourier transform performed is a two-dimensional transform. Alocation of the rectangular window is determined based on the detectionsection, for example, a minimum index and a maximum index of therectangular window in the horizontal direction are determined asfollows.

$\begin{matrix}\left\{ \begin{matrix}{k_{\min}^{h} = \left\lbrack {N_{h} - {N_{h}\frac{D_{1}}{\lambda}{\cos \left( \beta_{\min} \right)}{\cos \left( \theta_{\min} \right)}}} \right\rbrack} \\{k_{\max}^{h} = \left\lbrack {N_{h} - {N_{h}\frac{D_{1}}{\lambda}{\cos \left( \beta_{\max} \right)}{\cos \left( \theta_{\max} \right)}}} \right\rbrack}\end{matrix} \right. & (3)\end{matrix}$

A minimum index and a maximum index of the rectangular window in thevertical direction are determined as follows.

$\begin{matrix}\begin{Bmatrix}{k_{\min}^{v} = \left\lbrack {N_{v} - {N_{v}\frac{D_{2}}{\lambda}{\sin \left( \beta_{\max} \right)}}} \right\rbrack} \\{k_{\max}^{v} = \left\lbrack {N_{v} - {N_{v}\frac{D_{2}}{\lambda}{\sin \left( \beta_{\min} \right)}}} \right\rbrack}\end{Bmatrix} & (4)\end{matrix}$

where [θ_(min),θ_(max)] a detection range of the angle of arrival in thehorizontal direction, [β_(min),β_(max)] a detection range of the angleof arrival in the vertical direction, D is an antenna space in thehorizontal direction, and D₂ is an antenna space in the verticaldirection, X is a wavelength of a received signal, N_(h) is the numberof points involved in the discrete Fourier transform in the horizontaldirection, and N_(v) is the number of points involved in the discreteFourier transform in the vertical direction. Similarly, a filtering waybased on convolution can be used rather than the discrete Fouriertransform, which is not described repeatedly here any more.

The estimation for channel coefficients in the horizontal direction andthe vertical direction obtained after the inverse discrete Fouriertransform are h_(h) and h_(v), respectively. A whole channel estimationcan be acquired by combining the acquired channel estimation in variousdirections via h_(h)⊗h_(v) for example, where ⊗ represents the kroneckerproduct. In addition, although only an antenna array having a singlepolarization direction is described above, the channel estimation methodabove can also be applied to a case of cross polarization. For example,the transform and the filtering processing described above are performedin each polarization direction, estimation for channel coefficients in afirst polarization direction is h′_(h) and h′_(v), estimation forchannel coefficients in a second polarization direction is h″_(h) andh″_(v), and the whole estimation for the channel coefficients may berepresented by [h′_(h)⊗h′_(v), h″_(h)⊗h″_(v)]. It can be understoodthat, in a case that the antenna array has more polarization directions,the estimation for channel coefficients in all polarization directionscan be combined in a similar way, so as to acquire the whole estimationfor the channel coefficients.

In addition, it should be understood that although the rectangularwindow is used in the example described above, other window functionssuch as the hamming window or the Blackman window can be used besidesthe rectangular window. Correspondingly, in the convolution basedfiltering, a spatial-domain filter acquired by performing the inversediscrete Fourier transform on the window function described above can beused.

The apparatus 300 performs channel estimation based on the geographicallocation of the communication device, thereby improving accuracy of thechannel estimation, reducing the pilot pollution and improving theperformance of the system. In addition, in a case that the communicationdevice transmits data to the apparatus 300, the apparatus 300 mayfurther include a demodulation module (not shown in the Figure). Thedemodulation module can demodulate a data signal by using the channelestimation result obtained in the channel estimation way describedabove, in a case that the communication device transmits the pilotsequence (for example SRS) within a data transmission bandwidth, so asto obtain demodulated data with higher accuracy.

In an optional example of the present disclosure, the apparatus 300includes a synchronization module (not shown in the Figure). Thesynchronization module 300 performs a correlation operation on the firstuplink pilot sequence and the signal carrying the first uplink pilotsequence received by the apparatus 300, to determine an offset of thefirst uplink pilot sequence, and therefore determine information ontiming advance of the communication device which transmits the firstuplink pilot sequence and provide it to the communication device,thereby synchronizing the communication device with the apparatus 300.In the optional example, at least since the pilot sequence is allocatedbased on the interferences among cell partitions previously, timingadvance determined by the synchronization module for a communicationdevice corresponding to a specific uplink pilot would be more accurate.

In addition, the cell described here may include a macro cell and asmall cell. That is, the embodiment of the present disclosure can beapplied to a scenario of heterogeneous network. In a case that the smallcell is included, the number of cell partitions within the small cellcan be less than the number of cell partitions within the macro cell.Alternatively, the small cell is not divided, and is served as a cellpartition as a whole.

FIG. 7 shows a possible pilot pattern in a single-cell heterogeneousnetwork, in which, a whole hexagon represents a macro cell, and a graydot represents a small cell. Assuming that the number of uplink pilotsequences orthogonal to each other is 12, the macro cell is uniformlydivided into 12 cell partitions based on an angle of arrival in thehorizontal direction to the access point, also 4 small cells are locatedwithin the macro cell, and each small cell supports 2 users at most.

In a case that a traditional method is used, since it is necessary toensure that uplink pilot sequences used by users within the small celland users within the macro cell are orthogonal to each other, the macrocell can support only four users when all of the small cells are in aservice state. However with the channel estimation method including thefiltering according to the embodiment, as long as an angle of arrival ofa small cell can be distinguished from an angle of arrival of a cellpartition which uses a same uplink pilot sequence as the small cell, itwill do.

In FIG. 7, a number of a macro cell partition represents a number of anuplink pilot sequence used by the cell partition which is determined bythe pilot determining unit 102. For example, an uplink pilot sequence 1is used by a cell partition numbered 1. Uplink pilot sequences 1 and 2are used by a small cell numbered 1, uplink pilot sequences 3 and 4 areused by a small cell numbered 2, uplink pilot sequences 5 and 6 are usedby a small cell numbered 3, and uplink pilot sequences 7 and 8 are usedby a small cell numbered 4. A pilot pattern illustrated here is onlyexemplary, and is not limited thereto, as long as the pilot patternmeets the following condition: a cell partition and a small cell whichuse the same uplink pilot sequence can be distinguished by the angle ofarrival, thereby reducing interferences between the user of the smallcell and the user of the macro cell by the operation of the channelestimation unit 301.

In the example, since a part of uplink pilot sequences are multiplexedbetween the small cell and the cell partition of the macro cell, thenumber of users capable of being served by the macro cell simultaneouslyis raised from 4 to 12, thereby significantly improving the overallperformance of the system.

In addition, although only a pilot allocation way in a single-cellheterogeneous network is given in the embodiment, the conclusion is alsoapplicable to a multi-cell heterogeneous network.

Fourth Embodiment

In the process of describing the apparatus for wireless network in theembodiments described above, it is obvious that some processing andmethods are also disclosed. Hereinafter, an overview of the methods isgiven without repeating some details disclosed above. However, it shouldbe noted that, although the methods are disclosed in a process ofdescribing the apparatus for wireless communication, the methods do notcertainly employ or are not certainly executed by the aforementionedcomponents. For example, the embodiments of the apparatus for wirelesscommunication may be partially or completely implemented with hardwareand/or firmware, and the method for wireless communication describedbelow may be executed by a computer-executable program completely,although the hardware and/or firmware of the apparatus for wirelesscommunication can also be used by the methods.

FIG. 8 is a flowchart showing a method for wireless communicationaccording to an embodiment of the present disclosure, the methodincludes: determining a cell partition corresponding to a geographicallocation of a communication device, each cell including multiple cellpartitions (S11); and determining an uplink pilot sequence correspondingto the cell partition as an uplink pilot sequence of the communicationdevice (S12).

Specifically, the geographical location of the communication device maybe characterized by at least one of: an angle of arrival direction; anangle of arrival direction and a distance from the communication deviceto a base station: geographical coordinates; and an ID of a smell cellwhere the communication device is located.

In an example, in a case that it is determined in step S11 that thegeographical location of the communication device changes into anothersmall cell, an uplink pilot sequence of the small cell into which thecommunication device changes is determined as an uplink pilot sequenceof the user equipment in step S12.

As shown in a dashed-line block in FIG. 8, before step S11, the methodmay further includes receiving information indicating the geographicallocation transmitted by the communication device (S21). Also, after stepS12, the method may further include transmitting indicating informationof the uplink pilot sequence to the communication device via a dedicatedcontrol signaling to allocate the uplink pilot sequence to thecommunication device (522).

In an example, the method described above further includes: receivingpilot pattern information including a correspondence between each cellpartition and an uplink pilot sequence of the cell partition from acentral node (not shown in FIG. 8), and determining, based on the pilotpattern information, the uplink pilot sequence of the user equipment instep S12.

In another example, the method described above may further includereceiving uplink pilot sequence information of a cell partition withinanother cell adjacent to the cell partition where the communicationdevice is located (not shown in FIG. 8); and determining, based on theuplink pilot sequence information of the cell partition within anothercell, an uplink pilot sequence corresponding to the cell partition wherethe communication device is located in step S12.

Returning back to FIG. 8, in order to enable adjacent cell partitionscorrespond to different uplink pilot sequences, the method describedabove may further include: receiving a signal carrying a first uplinkpilot sequence (531); and performing, based on the signal carrying thefirst uplink pilot sequence, channel estimation on the communicationdevice to which the first uplink pilot sequence is allocated (S32),where filtering is performed during the channel estimation based on thegeographical location of the communication device to which the firstuplink pilot sequence is allocated, to obtain a channel estimationresult matching the communication device.

In an example, step S32 includes sub steps as shown in FIG. 9:performing, based on the signal carrying the first uplink pilot sequenceand the first uplink pilot sequence, coarse estimation on channelcoefficients (S321); and performing, based on the geographical locationof the communication device to which the first uplink pilot sequence isallocated, filtering on the coarse estimation for the channelcoefficients (S322).

Specifically, in step S322, the filtering can be performed by performingdiscrete Fourier transform on the coarse estimation for the channelcoefficients and windowing a result of the transform. A specific way ofthe filtering has been described in detail in the third embodiment,which is not repeated here any more.

Fifth Embodiment

FIG. 10 is a structural block diagram showing an apparatus 400 forwireless communication according to an embodiment of the presentdisclosure. The apparatus 400 includes: a dividing unit 401, configuredto divide each of multiple cells into multiple cell partitions; and apilot pattern generating unit 402, configured to correspond multipleuplink pilot sequences with the cell partitions to generate a pilotpattern, where the pilot pattern is generated based on pilotinterferences between different cell partitions which are correspondingto a same uplink pilot sequence.

It can be seen that the apparatus 400 plays the role of a centralcontrol node, and allocates the uplink pilot sequences by generallytaking the pilot interferences between all cell partitions within acontrol range thereof into consideration.

Specifically, the dividing unit 401 can divide each of the cells intocell partitions having different shapes and sizes. For example, in acase that a one-dimensional evenly spaced linear antenna array is usedfor an access point, a dividing method shown in FIG. 11 can be used,that is, the cell is divided into different cell partitions only basedon an angle of arrival in the horizontal direction to the access point.The dividing method is simple and easy to implement, in which, onlyinterferences in the horizontal direction is mainly considered. In acase that a two-dimensional antenna array such as an evenly spacedplanar array (shown in FIG. 2) is used for the access point, the accesspoint not only has a resolution in the horizontal direction, but alsohas a resolution in the vertical direction. In this case, both the angle(the angle of arrival in the horizontal direction) and a distance/anangle of arrival in the vertical direction may be considered in thedividing, thereby improving the accuracy of the system. A possibledividing method is shown in FIG. 12.

It should be noted that, FIG. 11 and FIG. 12 only show two special casesin dividing. Actual dividing can be determined based on cell deployment,and the cell partition can be designed to have an irregular shape basedon for example detection accuracy for the geographical location of theuser equipment.

In an example, the dividing unit 401 is configured to divide the cellinto the cell partitions based on a distribution status of thecommunication devices within the cell. For example, in a case that asmall cell is in a sleeping state since there is no user equipment to beserved by the small cell within a preset time period, the dividing unit401 can re-divide the cell into cell partitions without taking the smallcell as a cell partition. The pilot pattern generating unit 402regenerates a pilot pattern in a case that the dividing for the cellchanges. The changing here may mean that the change in the dividing forthe cell exceeds a certain extent, which can be measured according tovarious standards. It can be seen that, in this case, the pilot patternis updated dynamically, and an update frequency can be controlled.

Preferably, after the cell is divided into cell partitions, the pilotpattern generating unit 402 is configured to generate a pilot patternbased on pilot interferences between different cell partitions which arecorresponding to a same uplink pilot sequence.

For example, the pilot pattern generating unit 402 may generate thepilot pattern by minimizing a cost function as follows.

R ₁ =f ₁(p)  (5)

where p represents a pilot pattern, the cost function f₁ is a functionin direct proportion to an average inter-cell interferences, and thecost function f₁ is used to measure the average inter-cell interferencesborn by the system in a case that pilot pattern p is used.

As an example, in a case that a one-dimensional evenly-spaced linearantenna array is used for the access point, in order to minimize theinter-cell interferences, the cost function f₁ may be selected as:

$\begin{matrix}{f_{1} = {{\sum\limits_{m}^{\;}\; {\sum\limits_{l}^{\;}\; {\sum\limits_{s}^{\;}\; R_{msl}}}} = {\sum\limits_{m}^{\;}\; {\sum\limits_{l}^{\;}\; {\sum\limits_{s}^{\;}\; \frac{{{t\left( \theta_{msm} \right)}^{H}{t\left( \theta_{msl} \right)}}}{d_{msl}^{\gamma}}}}}}} & (6)\end{matrix}$

where R_(msl) is a metric for measuring an interference of a virtualuser located in the center of an s-th cell partition within an l-th cellon an s-th cell partition in an m-th cell, θ_(msn) is an angle ofarrival of a virtual user located in the center of the s-th cellpartition within the m-th cell with respect to an access point in them-th cell, θ_(msl) is an angle of arrival of a virtual user located inthe center of the s-th cell partition within the l-th cell with respectto the access point in the m-th cell, d_(msm) is a distance from avirtual user located in the center of the s-th cell partition within them-th cell to the access point in the m-th cell, γ is a path loss indexdefined in advance, and a vector t(θ)=[cos(θ), sin(θ)]^(T) is adirection vector in a unit length. The center of the cell partitionherein for example refers to a geometric gravity center of the cellpartition.

In formula (6), the numerator is to measure a correlation degree betweenangles of arrival direction of different users with respect to a certainaccess point, and the denominator is to measure a distance from aninterfering cell partition to an access point within the interferedcell. Since the inter-cell interferences are related to both the angleof arrival direction and the distance of the interfering user, theinter-cell interferences born by all users within the whole system aremeasured accurately by formula (6) above.

In another aspect, in a case that two-dimensional antenna array (asshown in FIG. 2) is used for the access point, in order to minimize theinter-cell interferences, the cost function f₁ is represented as:

$\begin{matrix}{f_{1} = {{\sum\limits_{m}{\sum\limits_{l}{\sum\limits_{s}R_{msl}}}} = {\sum\limits_{m}{\sum\limits_{l}{\sum\limits_{s}\frac{{{t\left( {\theta_{msm},\beta_{msm}} \right)}^{H}{t\left( {\theta_{msl},\beta_{msl}} \right)}}}{d_{msl}^{\gamma}}}}}}} & (7)\end{matrix}$

where θ_(msm) is a sight-distance angle of arrival in the horizontaldirection of a virtual user located in the center of an s-th cellpartition within an m-th cell with respect to an access point in them-th cell, θ_(msl) is a sight-distance angle of arrival in thehorizontal direction of a virtual user located in the center of an s-thcell partition within the l-th cell with respect to an access point inthe m-th cell, β_(msm) is a sight-distance angle of arrival in thevertical direction of a virtual user located in the center of the s-thcell partition within the m-th cell with respect to the access point inthe m-th cell, β_(msl) is a sight-distance angle of arrival in thevertical direction of a virtual user located in the center of the s-thcell partition within the l-th cell with respect to the access point inthe m-th cell. A direction vector in a unit length is represented asformula (8).

t(θ,β)[cos(θ)cos(β)sin(θ)cos(β)sin(β)]^(T)  (8)

A specific form of the cost function is given above, however, the costfunction is not limited thereto, and any cost function which can reflectthe average inter-cell interferences born by the system can be used. Inaddition, the pilot pattern can be generated by maximizing a utilityfunction as follows.

R ₂ =f ₂(p)  (9)

where the function f₂ is a function in direct proportion to a sum rateof the cell, and is used to measure the performance of the system whenthe pilot pattern p is used.

How the pilot pattern generating unit 402 generates the pilot pattern byusing the cost function f₁ is described below. It can be understoodthat, without considering the complexity, the cost function f₁ can beminimized by performing traversal search on all cell partitions, togenerate the pilot pattern. However, the computing complexity in thiscase is very high.

As an example, the pilot pattern generating unit 402 may be configuredto, with respect to a cell partition to which an uplink pilot sequencehas been allocated, calculate interferences of the cell partition on allcell partitions adjacent to the cell partition, and allocate the sameuplink pilot sequence to an adjacent cell partition on which theinterference is minimum.

Returning back to FIG. 11, for example, uplink pilot sequences have beenallocated for the 12 cell partitions of the cell (cell 0) in the center.Numbers 1 to 12 are used to represent the cell partitions and theallocated uplink pilot sequences orthogonal to each other (or groups ofthe uplink pilot sequences). The adjacent cell partitions of these cellpartitions are defined as all other cell partitions within a thickdashed line in an example. For a cell partition for example cellpartition 1 to which the uplink pilot sequence has been allocated, acell partition in the adjacent cell partitions on which the interferenceis minimum is selected and allocated the same uplink pilot sequence. Theinterference for example can be measured by R_(msl) in formula (6)described above. The operation described above is repeated, until noadjacent cell partition can be searched for the cell partitions (thatis, cell partitions 1 to 12) to which the uplink pilot sequences havebeen allocated. For the remaining cell partitions, a pilot allocationway based on a traversal search can be used. Returning back to FIG. 6,it shows an example of a pilot pattern acquired by the pilot allocationprocess described above.

In addition, for a remaining cell partition, a pilot allocation way inwhich an uplink pilot sequence different from the uplink pilot sequenceof each of the cell partitions directly adjacent to the remaining cellpartition is allocated can also be used, to further reduce the computingcomplexity. It should be understood that FIG. 11 and FIG. 6 only showexamples of the cell dividing and the pilot pattern generation, anapplication scope of the present disclosure is not limited thereto.

It should be noted that although one uplink pilot sequence is allocatedto each cell partition in the above example, a group of uplink pilotsequences may also be allocated to each cell partition. The uplink pilotsequences in each group of the uplink pilot sequences are orthogonal toeach other. Also, different groups of uplink pilot sequences can beallocated to adjacent cell partitions, to reduce interferences betweenusers.

As described above, the multiple cells described above may include amacro cell and a small cell, and the number of cell partitions withinthe small cell is less than the number of cell partitions within themacro cell.

In addition, as an example, in a case that a coverage range of the smallcell is small, the small cell can be not divided, and the small cell istaken as a cell partition as a whole. In this case, the dividing unit401 divides only the macro cell.

In a traditional method, in order to ensure that there are no mutualinterferences between a user of the small cell and a user of the macrocell, both the user of the macro cell and the user of the small cell usepilots orthogonal to each other. In this case, in order to ensureorthogonality of the pilots, the number of users supported by the macrocell is decreased. With the technology according to the embodiment, thesmall cell is also taken as an interference source, and the number ofusers served by the macro cell can be increased with the resulting pilotpattern, thereby significantly improving the whole performance of thesystem.

For ease of understanding the improvement for the performance of thesystem according to the embodiment, a specific simulation example isgiven below. In the example, cell construction and a cell dividing modeshown in FIG. 11 are adopted. That is, assuming that there are sevenhomogeneous cells and the one-dimensional evenly spaced linear antennaarray is used for the access point, the number of users in each cell is12 and each cell is divided into twelve cell partitions based on a rangeof an angle of arrival in the horizontal direction to the access point,and assuming that the ranges of the angles of arrival of cell partitionsto the access point thereof are the same. The cell in the center is atarget cell, and an object of the simulation research is the inter-cellinterferences subjected by a user in the target cell and an achievablehighest uplink data rate and an achievable highest downlink data rate.The traditional method is compared with the case of using the apparatus300 according to the third embodiment.

As described above, a pilot pattern shown in FIG. 6 is generated in theway according to the embodiment. In FIG. 6, a number of each cellpartition represents a sequence number of a group of uplink pilotsequences used by the cell partition, that is, a group 1 of uplink pilotsequences is used by users within the cell partition numbered 1.

A multipath channel model as follows is used in simulation.

$\begin{matrix}{h_{ml} = {\frac{1}{\sqrt{P}}{\sum\limits_{p = 1}^{P}\; {{a\left( \theta_{p} \right)}\gamma_{p}}}}} & (10)\end{matrix}$

where h_(ml) is a channel vector from a user within a l-th cell to anaccess point of an m-th cell, p is the number of multiple paths, θ_(p)is an angle of arrival from a p-th multipath to the access point of them-th cell; γ_(p) is a large-scale fading coefficient of a p-th path, avector a(θ) is a gradient vector of the angle θ of arrival, which isrepresented as:

$\begin{matrix}{{a(\theta)} = \left\lbrack {1,{\exp \left\{ {{- j}\; 2\pi \frac{D}{\lambda}{\cos (\theta)}} \right\}},L,{\exp \left\{ {{- j}\; 2\pi \frac{\left( {M - 1} \right)D}{\lambda}{\cos (\theta)}} \right\}}} \right\rbrack^{T}} & (11)\end{matrix}$

where D is a space between antennas of the access point, λ is awavelength of the received signal, L is a number of a cell (from 0 to 6in the example). Other parameters used in the simulation is specificallydescribed as follows: a radius of the cell is equal to 500 meters, apath loss coefficient is equal to 3.5, shadow fading variance is equalto 8 dB, a carrier frequency is equal to 2 GHz, a space between antennasis half of the signal wavelength, the number of multiple paths is equalto 50, and angular spread is equal to 10 degrees. Specifically, anangular spread distribution has two distribution models, one of thedistribution models is a uniform distribution, which can ensure thatangles of arrival of users within different cell partitions do notoverlay with each other, and the other of the distribution models is aGaussian distribution having a standard deviation of 10 degrees. Also,in order to ensure that users in a same cell can be distinguished bypilot-assisted means, a zero-forcing pre-coding algorithm is adopted topre-code downlink data, and a zero-forcing detecting algorithm isadopted to detect uplink data. For simplifying analysis, only ananalysis result for a user in the cell partition 1 is listed here.

A mean-square error of channel estimation for the access point isanalyzed first, and the mean-square error in simulation is calculated asfollows.

$\begin{matrix}{{{MSE}({dB})} = {10\; {\log_{10}\left( \frac{E\left\{ {{\hat{h} - h}}^{2} \right\}}{E\left\{ {h}^{2} \right\}} \right)}}} & (12)\end{matrix}$

where the vector h is a vector of an actual channel coefficient, and ĥis a vector of an estimated channel coefficient.

FIG. 13 is a simulation result of the mean-square error of the channelestimation, with respect to the two angular spread distribution models,i.e. the uniform distribution and Gaussian distribution, respectively.Specifically, in the traditional method, only coarse channel estimationis performed with the pilot assistance, and the subsequent filteringprocessing based on the geographical location of the communicationdevice is not performed. In addition, a filtering method according tothe embodiment is further shown, and the filtering method includes afiltering method based on the discrete Fourier transform and a filteringmethod using linear convolution.

As shown in FIG. 13, in a case that angles of arrival of users which usea same group of uplink pilot sequences do not overlap with each other,the mean-square error of the channel estimation can be decreasedsignificantly with the method according to the present disclosure, andthe mean-square error is decreased with the increase of the number ofantennas of the access point. However, in a case that angles of arrivalof users which use a same group of uplink pilot sequences overlap witheach other, the mean-square error of the channel estimation can not bedecreased significantly with the method according to the presentdisclosure, and the mean-square error of the channel estimation is notdecreased correspondingly with the increase of the number of antennas ofthe access point. Since with respect to the angular spread for theGaussian distribution, the angle of arrival is not completely limited toa certain range, and a part of multiple paths are filtered out by therectangular window in the filtering. In this case, the mean-square errorof the channel estimation can not be reduced even in a case that thenumber of antennas of the access point is increased.

Although the result in FIG. 13 indicates that in a case that angles ofarrival of users which use a same uplink pilot sequence overlap witheach other, the mean-square error of the channel estimation for theaccess point can not be decreased significantly, a subsequent simulationindicates that the method according to the present disclosure canimprove capacity of the system effectively. Accordingly, an uplinksignal to interference ratio (SIR) and a downlink signal to interferenceratio (SIR) are defined first. For example, an uplink signal tointerference ratio of a cell partition 1 of the center cell (defined ascell 0) is calculated as follows.

$\begin{matrix}{{SIR}_{1}^{uplink} = \frac{E\left\{ {{A_{10}h_{010}}}^{2} \right\}}{E\left\{ {{A_{10}{\sum\limits_{i \neq 0}^{\;}\; h_{01\; i}}}}^{2} \right\}}} & (13)\end{matrix}$

where h_(lsm) is a channel coefficient vector from an s-th cellpartition in an m-th cell to an access point of an l-th cell, a matrixA_(sm) is a detection matrix used by a user within the s-th cellpartition in the m-th cell, and the zero-forcing detecting algorithm isused in simulation.

A downlink signal to interference ratio of the cell partition 1 of thecenter cell is calculated as follows.

$\begin{matrix}{{SIR}_{1}^{downlink} = \frac{E\left\{ {{h_{010}^{T}W_{10}}}^{2} \right\}}{E\left\{ {{\sum\limits_{i \neq 0}^{\;}\; {h_{i\; 10}^{T}W_{1\; i}}}}^{2} \right\}}} & (14)\end{matrix}$

where W_(sm) is a pre-coding matrix used by a user in the s-th cellpartition in the m-th cell, and the zero-forcing pre-coding algorithm isused in simulation.

The uplink channel capacity and downlink channel capacity each can becalculated based on the signal to interference ratio, and thecalculating method is described as follows respectively.

C ₁ ^(uplink)=log₂ (1+SIR ₁ ^(uplink))  (15)

C ₁ ^(downlink)=log₂ (1+SIR ₁ ^(downlink))  (16)

FIG. 14 is an uplink channel capacity of the user in the cellpartition 1. As shown in FIG. 14, although the mean-square error of thechannel estimation can not be decreased in a case of angular spread ofGaussian distribution with the technology of the present disclosuredescribed above, the uplink channel capacity can also be increased withthe increase of the number of antennas of the access point. Comparedwith the angular spread of the uniform distribution, the uplink channelcapacity in a case of the Gaussian distribution still has some loss.FIG. 15 is a downlink channel capacity of the user in the cellpartition 1. Similar to FIG. 14, no matter whether the angular spreadconforms to the uniform distribution or the Gaussian distribution, thedownlink channel capacity can be raised with the increase of the numberof antennas of the access point in the method according to the presentdisclosure. Compared with the traditional method, a significant gain isacquired in the method according to the embodiment of the presentdisclosure.

It should be understood that, the system example is only illustrative,and is not to be considered to limit the scope of the presentdisclosure.

Sixth Embodiment

In the embodiment, the apparatus for wireless communication is a centralnode in communication with multiple cells. FIG. 16 is a structural blockdiagram showing an apparatus 500 for wireless communication according tothe embodiment. Besides the units the same as those in FIG. 8, theapparatus 500 further includes a communication interface 501 configuredto inform each cell of the pilot pattern corresponding to the cell.

The communication interface 501 may transmit the pilot pattern inresponse to a request of the cell, or transmit the pilot patternperiodically, or transmit a pilot patter in a case that the pilotpattern is generated renewedly.

In addition, in an example, each of the multiple cells may havedifferent on-off states. The pilot pattern generating unit 402 isconfigured to, with respect to different combinations of the on-offstates of the cell, generate the pilot pattern, and store as a mappingtable.

Since a change in the on-off state of the cell affects inter-cellinterference status, the pilot pattern is caused to be changed. Inparticular, in a case that a macro cell includes small cells, a changein the on-off state of a small cell occurs more frequently, and thepilot pattern generating unit 402 may generate a pilot pattern withrespect to all combinations of the on-off states and store the pilotpattern.

Correspondingly, the communication interface 501 may be configured torenewedly inform, based on the mapping table, each cell of acorresponding pilot pattern in a current on-off state, in the case thatthe on-off states of the cells change. Specifically, information on theuplink pilot sequences which are allocated to each small cell istransmitted to a base station corresponding to the small cell.Alternatively, the communication interface 501 may perform the informingperiodically.

Practically, the pilot pattern generating unit 402 may not store thepilot patterns with respect to all combinations of the on-off states inadvance, and generate the pilot pattern temporarily as needed.

By generating the pilot pattern with respect to different combinationsof the on-off states of the cell, the apparatus 500 may provide a pilotpattern suitable for a current environment to each cell, therebyimproving the performance of the system.

The apparatus 400 and the apparatus 500 can be, as a component (forexample a control chip), disposed in a management device such as aserver for managing multiple cells, for example a server on a corenetwork side, or a super controller (SRC)/Cloud BB (basic band) in anunbounded network solution (for example, C-RAN). In addition, theapparatus 400 and the apparatus 500 above may also be a managementdevice itself such as a server for managing multiple cells. The regularcomponents included in the apparatus 400 and the apparatus 500 are thesame as those components in the conventional technology, which are notdescribed repeatedly in the present disclosure any more.

Seventh Embodiment

In the process of describing the apparatus for wireless network in theembodiments described above, obviously, some processing and methods arealso disclosed. Hereinafter, an overview of the methods is given withoutrepeating some details disclosed above. However, it should be notedthat, although the methods are disclosed in a process of describing theapparatus for wireless communication, the methods do not certainlyemploy or are not certainly executed by the aforementioned components.For example, the embodiments of the apparatus for wireless communicationmay be partially or completely implemented with hardware and/orfirmware, the method for wireless communication described below may beexecuted by a computer-executable program completely, although thehardware and/or firmware of the apparatus for wireless communication canalso be used by the methods.

FIG. 17 is a flowchart showing a method for wireless communicationaccording to an embodiment of the present disclosure, and the methodincludes: dividing each of multiple cells into multiple cell partitions(S41): and corresponding multiple uplink pilot sequences with the cellpartitions, to generate a pilot pattern (S42), where the pilot patternis generated based on pilot interferences between different cellpartitions which are corresponding to a same uplink pilot sequence.

In step S41, the cell may be divided into the cell partitions accordingto a distribution status of communication devices within the cell. In acase that the dividing for the cell changes, step S42 is executed againto regenerate a pilot pattern.

The multiple cells described above include a macro cell and a smallcell, and the number of cell partitions within the small cell is lessthan the number of cell partitions within the macro cell. As an example,the small cell may not be divided, and the whole small cell is taken asa cell partition.

In an example, interferences of the cell partition to which the uplinkpilot sequence is allocated on all cell partitions adjacent to the cellpartition are calculated in step S42, and a same uplink pilot sequenceis allocated to an adjacent cell partition on which the interference isminimum.

The method described above can be executed at a central node incommunication with a base station corresponding to multiple cells. Asshown in a dashed-line block in FIG. 17, the method may further includeinforming a base station of each of the cells of the corresponding pilotpattern (S43).

In addition, each of multiple cells may have different on-off statesrespectively. In step S42, a pilot pattern is generated with respect todifferent combinations of the on-off states of the cells, and stored asa mapping table. In this case, in a case that the on-off states of thecells change, step S43 is executed again to inform a base station ofeach of the cells of a corresponding pilot pattern in the current on-offstate based on the mapping table.

The details of the method described above have been described in detailin the fifth embodiment and the sixth embodiment, which are not repeatedhere any more. In the method, the pilot pattern is generated bygenerally considering the interference between cells, therebysignificantly reducing the pilot pollution and improving the performanceof the system.

Eight Embodiment

A structural block diagram of an electronic device 600 according to anembodiment of the present disclosure is described below with referenceto FIG. 18. The electronic device 600 includes: an uplink pilot sequencedetermining unit 601, configured to determine, based on indicatinginformation of the uplink pilot sequence allocated by a base station, anuplink pilot sequence of the electronic device 600: and a locationdetermining unit 602, configured to determine a change in a geographicallocation of the electronic device 600. In a case that the geographicallocations of the electronic device 600 before and after changingcorrespond to different cell partitions, the uplink pilot sequencedetermining unit 601 updates the uplink pilot sequence of the electronicdevice 600 based on the indicating information of the uplink pilotsequence allocated by the base station, and the updated uplink pilotsequence corresponds to a cell partition corresponding to thegeographical location of the electronic device 600 after changing.

The indicating information of the uplink pilot sequence may be an indexindicating the uplink pilot sequence (for example, SRS-ConfigIndex inthe LTE standard), and may also be the uplink pilot sequence itself. Forexample, in the LTE standard, the indicating information may be includedin a dedicated control signaling transmitted by the base station, forexample a RRC signaling. In addition, the indicating information mayfurther be included in a broadcasting signal including the pilotallocating information transmitted by the base station. The uplink pilotsequence determining unit 601 determines the uplink pilot sequence forthe electronic device 600 by parsing the signaling described above.

In a case that the transmitted indicating information is the index, theelectronic device 600 and the base station have for example appointed acorrespondence between an index and an uplink pilot sequence in advance,and then the uplink pilot sequence determining unit 601 can determine anuplink pilot sequence to be used correctly.

The location determining unit 602 determines whether the location of theelectronic device 600 changes, for example, whether the location of theelectronic device 600 changes into a cell partition different from thecurrent cell partition. In a case that it is determined that thelocation of the electronic device 600 changes, it means that the uplinkpilot sequence used by the electronic device 600 may change. Therefore,the uplink pilot sequence determining unit 601 needs to update theuplink pilot sequence of the electronic device 600 to an uplink pilotsequence corresponding to the cell partition after the geographicallocation changing based on the indicating information of the uplinkpilot sequence allocated by the base station. In an example of thepresent disclosure, the location determining unit 602 includes a GPSmodule to determine the change in the location. In another example, thelocation determining unit 602 receives an ID of the small cellbroadcasted by a small cell base station to determine the change in thelocation of the electronic device 600. In addition, for example, in theLTE, the base station (eNodeB) can schedule each user equipment (UE) totransmit the SRS at one time or periodically. After the user equipmentin which the electronic device 600 described above is disposeddetermines the uplink pilot sequence based on the indicating informationof the uplink pilot sequence allocated by the base station, the userequipment may transmit the SRS signal corresponding to the cellpartition where the UE is located to the base station at one time orperiodically according to the scheduling of the base station.

The electronic device 600 described here may be a user equipment such asa mobile terminal, a vehicle, an intelligent wearable device or acomponent thereof, or may also be an infrastructure such as a small cellbase station or a component of the small cell base station. In a casethat the electronic device is the small cell base station, a macro basestation corresponding to the small cell base station allocatesindicating information of the pilot sequence to the small cell basestation.

The electronic device 600 according to the present disclosure may updatethe uplink pilot sequence to be used automatically based on the changein the geographical location thereof, thereby improving thecommunication quality.

Ninth Embodiment

FIG. 19 is a structural block diagram showing an electronic device 700according to another embodiment of the present disclosure. Besides thecomponents the same as those in FIG. 18, the electronic device 700further includes: a transmitting unit 701, configured to transmitinformation on the geographical location of the electronic device; and areceiving unit 702, configured to receive the indicating information ofthe uplink pilot sequence allocated by the base station.

Specifically, the transmitting unit 701 can transmit the information onthe geographical location by at least one of: transmitting periodically;transmitting when the location determining unit 601 determines that thechange in the location exceeds a predetermined range; and transmittingaccording to location updating request information of the base station.It can be understood that the transmitting unit 701 may transmit theinformation on the geographical location in any existing manner andsignal format. Particularly, in a case that the electronic device 700initially accesses in the network, the electronic device 700 cantransmit a signal by using a predetermined uplink pilot sequence or in arobust modulation format to report the information on the geographicallocation thereof.

The receiving unit 702 receives a dedicated control signaling includingthe indicating information of the uplink pilot sequence, and the uplinkpilot sequence determining unit 601 parses the dedicated controlsignaling to determine the uplink pilot sequence of the electronicdevice 700. The dedicated control signaling may be for example a RRCsignaling in the LTE standard.

In addition, the receiving unit 702 may further receive a broadcastingsignaling including the indicating information of the uplink pilotsequence, and the broadcasting signaling includes a correspondencebetween multiple cell partitions and multiple uplink pilot sequences.The uplink pilot sequence determining unit 601 parses the broadcastingsignaling and determines, based on a cell partition corresponding to acurrent location of the electronic device, the uplink pilot sequence ofthe electronic device. In this case, the transmitting unit 701 may nottransmit the information on the geographical location of the electronicdevice either.

The apparatus 700 transmits the information on the geographical locationthereof and receives the indicating information of the uplink pilotsequence allocated by the base station in various ways, and thus theuplink pilot sequence to be used can be changed flexibly, therebyimproving the performance of the communication system.

Tenth Embodiment

In the process of describing the electronic device in the embodimentsdescribed above, obviously, some processing and methods are alsodisclosed. Hereinafter, an overview of the methods is given withoutrepeating some details disclosed above. However, it should be notedthat, although the methods are disclosed in a process of describing theelectronic device, the methods do not certainly employ or are notcertainly executed by the aforementioned components. For example, theembodiments of the electronic device may be partially or completelyimplemented with hardware and/or firmware, the method for the electronicdevice described below may be executed by a computer-executable programcompletely, although the hardware and/or firmware of the electronicdevice can also be used in the methods.

As shown in FIG. 20, the method for the electronic device according tothe embodiment of the present disclosure includes: determining, based onthe indicating information of the uplink pilot sequence allocated by thebase station, an uplink pilot sequence of the electronic device (S51):and determining a change in a geographical location of the electronicdevice (S52). In a case that the geographical locations of theelectronic device before and after changing correspond to different cellpartitions, step S51 is executed again, to update the uplink pilotsequence of the electronic device based on the indicating information ofthe uplink pilot sequence allocated by the base station, and the updateduplink pilot sequence corresponds to a cell partition corresponding tothe geographical location of the electronic device after changing.

In addition, as shown in a dashed-line block in FIG. 20, the method mayfurther include: transmitting information on the geographical locationof the electronic device (S53); and receiving the indicating informationof the uplink pilot sequence allocated by the base station (S54).

In step S53, the information on the geographical location can betransmitted by at least one of: transmitting periodically; transmittingwhen it is determined in step S52 that the change in the locationexceeds a predetermined range; and transmitting according to locationupdating request information of the base station.

In an example, a dedicated control signaling including the indicatinginformation of the uplink pilot sequence can be received in step S54,and the dedicated control signaling is parsed in step S52 to determinethe uplink pilot sequence of the electronic device. The dedicatedcontrol signaling may be for example a RRC signaling in the LTEstandard.

In addition, a broadcasting signaling including the indicatinginformation of the uplink pilot sequence is received in step S54, andthe broadcasting signaling includes a correspondence between multiplecell partitions and multiple uplink pilot sequences. The broadcastingsignaling is parsed and the uplink pilot sequence of the electronicdevice is determined based on a cell partition corresponding to acurrent location of the electronic device in step S52. In this case,step S53 of transmitting the information on the geographical location ofthe electronic device may not be executed.

With the method described above, the used uplink pilot sequence can bechanged flexibly based on the change in the geographical location of theelectronic device, thereby improving communication quality. The detailsof the method have been described in detail in the eighth embodiment andthe ninth embodiment, which are not repeated here any more.

Eleventh Embodiment

FIG. 21 is a structural block diagram showing an apparatus 800 forwireless communication according to another embodiment of the presentdisclosure. The apparatus 800 includes: a pilot determining unit 801,configured to determine a first uplink pilot sequence for a firstcommunication device; and a channel estimation unit 802, configured toperform, based on a received signal carrying the first uplink pilotsequence, channel estimation on the first communication device, wherethe channel estimation unit 802 performs filtering during the channelestimation based on a geographical location of the first communicationdevice, to obtain a channel estimation result matching the firstcommunication device.

The pilot determining unit 801 may be the same as the pilot determiningunit 102 described in the first embodiment to the third embodiment, ormay use another way of determining the uplink pilot sequence, which isnot limited to the technology according to the present disclosure.

The channel estimation unit 802 may have a same structure as the channelestimation unit 301 described in the third embodiment. In an example,the channel estimation unit 802 may include: a coarse channel estimationmodule 3001, configured to perform, based on the signal carrying thefirst uplink pilot sequence and the first uplink pilot sequence, coarseestimation on channel coefficients; and a spatial filtering module 3002,configured to filter, based on the geographical location of the firstcommunication device, the coarse estimation for the channelcoefficients. An example of the structure and function of the channelestimation unit 802 has been described in detail in the thirdembodiment, which is not repeated here.

In the embodiment, the spatial filtering module 3002 may estimate thegraphical location of the first communication device based on the coarseestimation for the channel coefficients. For example, the geographicallocation of the first communication device may be characterized at leastby a direction of the first communication device with respect to theapparatus 800, such as an angle of arrival direction of a signal. It canbe understood that angles of arrival direction corresponding tocommunication devices in different geographical locations are different,and by filtering based on the angle of arrival direction, the spatialfiltering module 3002 can filter out the interferences from anothercommunication device, the location of which is greatly different fromthe location of the first communication device. Specifically, theanother communication device described here may be located in a samecell as the first communication device, or may be located in a differentcell from the first communication device. For example, in a case that asame or correlated uplink pilot sequence is used by adjacent cells,pilot pollution at an edge of the cells can be reduced in the presentdisclosure. For example, spatial multiplexing for the uplink pilotsignal within a same cell is feasible with the spatial filteringsolution according to the present disclosure, so that the same or thecorrelated uplink pilot sequence can be used by different communicationdevices within the same cell.

In an example, as shown in FIG. 22, the spatial filtering module 3002may include: an angular domain transform part 30021, configured toperform angular domain transform on the coarse estimation for thechannel coefficients; an angular domain filtering part 30022, configuredto perform filtering on the angular domain transform based on thedirection described above; and an inverse transform part 30033,configured to perform inverse Fourier transform on a result obtainedafter the filtering to obtain a channel estimation result.

Assuming that antenna array configuration of the base station isrepresented as (M, N, 2), that is, there are M×N antenna arrays withcross polarization. {circumflex over (θ)}′ and {circumflex over (ϕ)}′are used to represent preliminary estimation for an angle of arrival ina vertical direction and an angle of arrival in a horizontal directionfor a first polarization direction respectively, {circumflex over (θ)}″and {circumflex over (ϕ)}″ are used to represent preliminary estimationfor an angle of arrival in a vertical direction and an angle of arrivalin a horizontal direction for a second polarization direction, andpreset scattering angles are represented as σ_(θ) and σ_(ϕ). Inaddition, ĥ′_(e) and ĥ′_(a) represent coarse estimation for channelcoefficients in the vertical direction and in the horizontal directionfor the first polarization direction, respectively, and ĥ″_(e) andĥ″_(a) represent coarse estimation for channel coefficients in thevertical direction and in the horizontal direction for the secondpolarization direction, respectively, ĥ′_(e) and ĥ′_(a) are vectorshaving a length of M, respectively, and ĥ″_(e) and ĥ″_(a) are vectorshaving a length of N.

The angular domain transform part 30021 transforms ĥ′_(e), ĥ′_(a),ĥ″_(e)and ĥ″_(a) into the angular domain by using for example the Fouriertransform, respectively, as shown in formula (17):

$\begin{matrix}{{{{G_{e}^{\prime}(\omega)} = {\sum\limits_{m = 0}^{M - 1}\; {{{\hat{h}}_{e}^{\prime}(m)}e^{{- j}\; m\; \omega}}}}{{G_{a}^{\prime}(\omega)} = {\sum\limits_{n = 0}^{N - 1}\; {{{\hat{h}}_{a}^{\prime}(n)}e^{{- j}\; n\; \omega}}}}{G_{e}^{''}(\omega)} = {\sum\limits_{m = 0}^{M - 1}\; {{{\hat{h}}_{e}^{''}(m)}e^{{- j}\; m\; \omega}}}}{{G_{a}^{''}(\omega)} = {\sum\limits_{n = 0}^{N - 1}\; {{{\hat{h}}_{a}^{''}(n)}e^{{- j}\; n\; \omega}}}}} & (17)\end{matrix}$

The angular domain filtering part 30022 can acquire the preliminaryestimation {circumflex over (θ)}′ and {circumflex over (ϕ)}′ for theangle of arrival in the vertical direction and the preliminaryestimation {circumflex over (θ)}″ and {circumflex over (ϕ)}″ for theangle of arrival in the horizontal direction for the two polarizationdirections, and use a filter based on the preliminary estimation toperform filtering on the angular domain transform. For example, an anglecorresponding to a maximum value in the angular domain transform istaken as the preliminary estimation for the angle of arrival, and aband-pass filter centered on the preliminary estimation is used toperform filtering. An example of the filter is described in formula(18), where the width of the pass band can be set based on the presetscattering angle.

$\begin{matrix}{{\overset{\_}{G}(\omega)} = \left\{ \begin{matrix}{{G(\omega)},} & {\omega \in \left( {{\omega_{0} - {\sigma/2}},{\omega_{0} + {\sigma/2}}} \right)} \\{0,} & {others}\end{matrix} \right.} & (18)\end{matrix}$

where G(ω) is one of the formulas (17), ω₀ is estimation on an angle ofarrival corresponding to the direction and polarization, and σ is thescattering angle corresponding to the direction.

Then, the inverse transform part 30033 performs inverse Fouriertransform on the result obtained after the filtering to obtain a channelestimation result. The channel estimation result can be represented informula (19) below by combining the filtering and the inverse transform.

$\begin{matrix}{{{{\overset{\_}{h}}_{e}^{\prime}(m)} = {\frac{1}{2\; \pi}{\int_{{\hat{\theta}}^{\prime} - \frac{\sigma_{\theta}}{2}}^{{\hat{\theta}}^{\prime} + \frac{\sigma_{\theta}}{2}}{{G_{e}^{\prime}(\omega)}e^{j\; m\; \omega}d\; \omega}}}}{{{\overset{\_}{h}}_{a}^{\prime}(n)} = {\frac{1}{2\; \pi}{\int_{{\hat{\varphi}}^{\prime} - \frac{\sigma_{\theta}}{2}}^{{\hat{\varphi}}^{\prime} + \frac{\sigma_{\theta}}{2}}{{G_{a}^{\prime}(\omega)}e^{j\; n\; \omega}d\; \omega}}}}{{{\overset{\_}{h}}_{e}^{''}(m)} = {\frac{1}{2\; \pi}{\int_{{\hat{\theta}}^{''} - \frac{\sigma_{\theta}}{2}}^{{\hat{\theta}}^{''} + \frac{\sigma_{\theta}}{2}}{{G_{e}^{''}(\omega)}e^{j\; m\; \omega}d\; \omega}}}}{{{\overset{\_}{h}}_{a}^{''}(n)} = {\frac{1}{2\; \pi}{\int_{{\hat{\varphi}}^{''} - \frac{\sigma_{\varphi}}{2}}^{{\hat{\varphi}}^{''} + \frac{\sigma_{\varphi}}{2}}{{G_{a}^{''}(\omega)}e^{j\; n\; \omega}d\; \omega}}}}} & (19)\end{matrix}$

For example, the overall channel estimation can be acquired by combiningthe acquired channel estimation in each direction and each polarizationvia the following formula (20).

h =[ h′ _(e) ⊗h′ _(a) ,h″ _(e) ⊗h″ _(a)]  (20)

where ⊗ represents the kronecker product. It should be noted thatalthough specific formulas for angular domain transform and filteringare shown here, which are not limited thereto, and any way oftransforming the coarse estimation for the channel coefficients into theangular domain can be used.

As another example, the angular domain filtering part 30022 may alsodesign a filter based on the preliminary estimation using empiricalvalues. For example, a bandwidth of the filter shown in formula (18) canbe set according to empirical values such as an empirical angle spread,estimation deviation for the angle of arrival and the like.

It can be seen that the spatial filtering module 3002 may reduceinterferences of a signal carrying the correlated uplink pilot sequencefrom a communication device in other directions.

In addition, as shown in FIG. 23, the channel estimation unit 802 mayfurther include: an iterating module 8021, configured to provide thechannel estimation result acquired by the inverse transform part 30033as the coarse estimation for the channel coefficients to the spatialfiltering module 3002, to further perform filtering. Since the channelestimation result acquired by the inverse transform part 30033 hasfiltered out a part of interferences, the angular domain filtering part30022 may acquire a more accurate estimation value for the angle ofarrival based on the channel estimation result, thereby performing moreaccurate filtering, and further improving the channel estimation result.

The signal carrying the first uplink pilot signal described above may befor example a Sounding Reference Signal (SRS) or an uplink demodulationreference signal (DMRS). A downlink reference signal after beamformingmay be for example at least one of a cell reference signal after thebeamforming and a channel state information reference signal after thebeamforming.

In addition, an example of estimating an approximate geographicallocation (for example direction) of the communication device by coarseestimation for the channel coefficients is described above, however,other ways can be used. For example, estimation is performed on forexample the angle of arrival based on a measurement report of thecommunication device for the downlink reference signal after thebeamforming, and then filtering is performed based on the estimation.Specifically, the apparatus 800 performs beanmforming processing on thedownlink reference signal, transmits a reference signal obtained afterthe beamforming processing to different directions for example in a timedivision manner, and receives a measurement report fed back from thecommunication device served by the apparatus 800. For example, a beamdirection corresponding to a strongest measurement result is taken as anangle of arrival of the communication device. In addition, directionestimation may be performed for example by the cell partition where thecommunication device is located, for example, {circumflex over (θ)}′ and{circumflex over (ϕ)}′ as well as {circumflex over (θ)}″ and {circumflexover (ϕ)}′ described above can be determined based on the ID of the cellpartition. It can be understood that estimation for the angle of arrivaldirection can be acquired according to the conventional technology suchas feedback of a positioning reference signal and GPS positioninginformation, which is not enumerated here. The operation about thesubsequent filtering and the inverse transform described above is alsoapplicable in this case.

As described above, the channel estimation unit 802 performs filteringduring the channel estimation based on the geographical location of thefirst communication device. The channel estimation unit 802, by makinguse of a distribution difference of channel coefficients caused bydifference of geographical locations of the communication devices,filter out a channel response of the communication devices, except thetarget communication device, i.e. the first communication device, whichuse the same uplink pilot sequence. Therefore, at least one of thefollowing can be realized: reducing uplink pilot sequence interferencesbetween cells or within a cell, effectively reducing the mean-squareerror of the channel estimation, and improving the capacity of thecommunication system. In addition, a feasible way for spatialmultiplexing of the uplink pilot sequence is provided. Especially in acase that the coherent bandwidth is small and the relative mobility ishigh, more communication devices can be supported.

In an example, the apparatus 800 may be operated as a base station, thefirst communication device is a user equipment, and the apparatus 800may further include a transceiver unit configured to receive the signaldescribed above.

Similarly, In the process of describing the apparatus for wirelessnetwork in the embodiments described above, obviously, some processingand methods are also disclosed. Hereinafter, an overview of the methodsis given without repeating some details disclosed above. However, itshould be noted that, although the methods are disclosed in a process ofdescribing the apparatus for wireless communication, the methods do notcertainly employ or are not certainly executed by the aforementionedcomponents. For example, the embodiments of the apparatus for wirelesscommunication may be partially or completely implemented with hardwareand/or firmware, the method for wireless communication described belowmay be executed by a computer-executable program completely, althoughthe hardware and/or firmware of the apparatus for wireless communicationcan also be used in the methods.

As shown in FIG. 24, a method for wireless communication is provided,which includes: determining a first uplink pilot sequence of a firstcommunication device (S61); and performing, based on a received signalcarrying the first uplink pilot sequence, channel estimation on thefirst communication device (S62). Filtering is performed during thechannel estimation based on the geographical location of the firstcommunication device, to obtain a channel estimation result matching thefirst communication device.

In an example, step S62 may include the following sub-steps: a)performing, based on the signal carrying the first uplink pilot sequenceand the first uplink pilot sequence, coarse estimation on channelcoefficients; b) performing, based on the geographical location of thefirst communication device, filtering on the coarse estimation for thechannel coefficients.

As an example, the geographical location of the first communicationdevice can be estimated according to the coarse estimation for thechannel coefficient. Specifically, the geographical location of thefirst communication device can be characterized at least by a directionof the first communication device with respect to the base station, forexample, an angle of arrival direction of the signal.

In another example, the geographical location of the first communicationdevice can also be estimated based on the measurement result for thereference signal obtained after beamforming from the first communicationdevice. The downlink reference signal after the beamforming is forexample at least one of a cell reference signal after the beamformingand the channel state information reference signal after thebeamforming.

FIG. 25 is a flowchart showing the sub-steps of an example of performingfilter based on the geographical location. As shown in FIG. 25, thesub-steps include: performing angular domain transform on the coarseestimation for the channel coefficients (S6201); performing filtering onthe angular domain transform based on the direction described above(S6202); and performing inverse Fourier transform on a result obtainedafter the filtering to obtain a channel estimation result (S6203).

Specifically, in step S6202, an angle corresponding to a maximum valueof the angular domain transform is taken as preliminary estimation, anda band-pass filter centered on the preliminary estimation is used toperform the filtering. The bandwidth of the filter based on thepreliminary estimation can further be designed according to empiricalvalues.

In addition, the sub-step b) in step S62 may be executed iteratively,that is, the channel estimation result acquired in step S6203 is takenas the coarse estimation for the channel coefficients, to furtherperform the filtering. In this way, the accuracy of the channelestimation can be further improved.

The signal described herein includes an uplink reference signal, forexample a Sounding Reference Signal (SRS) or an uplink demodulationreference signal (DMRS).

Implementation for each step in the method has been described in detailin the third embodiment, the fourth embodiment and the description forthe apparatus of the present embodiment, which is not repeated here anymore.

Twelfth Embodiment

FIG. 26 is a structural block diagram showing an apparatus 900 forwireless communication according to another embodiment of the presentdisclosure. As shown in FIG. 26, besides the components in the apparatus800, the apparatus 900 further includes a reconfiguration unit 901configured to reconfigure, based on the geographical location of thefirst communication device and a geographical location of anothercommunication device to which an uplink pilot sequence has beenallocated, an uplink pilot sequence for the first communication device,to enable two or more communication devices within a same cell tomultiplex non-orthogonal uplink pilot sequences.

Specifically, in a case that the first communication device requests toaccess into a cell where the apparatus 900 is located, the pilotdetermining unit 801 allocates an initial first uplink pilot sequencefor the first communication device, and the channel estimation unit 802estimates a geographical location of the first communication devicebased on a signal carrying the first uplink pilot sequence uponreceiving the signal, performs spatial filtering during the channelestimation based on the geographical location to acquire a more accuratechannel estimation result. The reconfiguration unit 903 may reallocatean uplink pilot sequence for the first communication device, based onthe geographical location described above and a geographical location ofanother communication device to which an uplink pilot sequence has beenallocated. For example, the reallocated uplink pilot sequence is thesame as or is correlated to an uplink pilot sequence which is being usedby a communication device within the same cell. Mutual interferencesbetween the communication devices can be avoided by performing thespatial filtering during the channel estimation, and therefore, spatialmultiplexing for the pilot sequence within the cell can be realized.

In the example, the channel estimation unit 802 is configured to acquirethe geographical location of the first communication device and performthe channel estimation. In an aspect, the reconfiguration unit 902 mayreconfigure the first uplink pilot sequence allocated to the firstcommunication device based on the geographical location and thegeographical location of another communication device to which an uplinkpilot sequence has been allocated. In another aspect, the base stationcan receive and demodulate the signal based on the channel estimationresult, and so on.

An example of the structure and function of the channel estimation unit802 has been described in detail in the eleventh embodiment, which isnot repeated here.

In an example, the pilot determining unit 802 is configured to determinea first uplink pilot sequence orthogonal to the uplink pilot sequence ofanother communication device to which the uplink pilot sequence has beenallocated for the first communication device. For example, the pilotdetermining unit 801 may operate when the first communication device isinitially accessed. In addition, the pilot determining unit 801 maydetermine the first uplink pilot sequence in the way described in thefirst embodiment.

In addition, in a case that the first communication device is in mobilestate, for example, the channel estimation unit 802 may estimate achange in the location of the first communication device, and thereconfiguration unit 901 adjusts, based on a change in a location of thefirst communication device with respect to the geographical location ofanother communication device to which the uplink pilot sequence has beenallocated, the uplink pilot sequence allocated for the firstcommunication device.

For example, a non-orthogonal uplink pilot sequence (the same uplinkpilot sequence or a correlated uplink pilot sequence) (referred as thesecond uplink pilot sequence) can be multiplexed by the firstcommunication device with a second communication device to which anuplink pilot sequence is allocated. The location of the secondcommunication device is greatly different from the location of the firstcommunication device. In a case that the location of the firstcommunication device is characterized by a direction (for example, anangle of arrival direction of a signal) of the first communicationdevice with respect to the apparatus 900, for example, an angle ofarrival direction of the first communication device is greatly differentfrom an angle of arrival direction of the second communication device.

In a case that the reconfiguration unit 901 configures the firstcommunication device and the second communication device to multiplexthe second uplink pilot sequence, the channel estimation unit 802performs channel estimation on the first communication device based on areceived signal carrying the second uplink pilot sequence. Similarly,the filtering is perform during the channel estimation based on thegeographical location of the first communication device. Since thelocation of the first communication device is greatly different from thelocation of the second communication device, interferences from thesecond communication device can be filtered out, and an accurate channelestimation result can also be acquired. In other words, the apparatus900 enables communication devices in the same cell to spatiallymultiplex the correlated uplink pilot sequences.

Correspondingly, in a case that the location of the first communicationdevice is close to the location of the second communication device, thereconfiguration unit 901 configures uplink pilot sequences which areorthogonal to each other for the first communication device and thesecond communication device respectively.

For example, the signal described above may include an uplink referencesignal. An example of the uplink reference signal includes but is notlimited to SRS and uplink DMRS. Operations of estimating thegeographical location of the communication device and performing channelestimation while considering the spatial filtering have been describedin detail in the eleventh embodiment, which is not repeated here anymore.

In addition, as shown in a dashed-line block in FIG. 26, the apparatus900 may further include a dividing unit 902 configured to divide a cellwhere the apparatus is located into multiple cell partitions. Thereconfiguration unit 901 is configure to reconfigure an uplink pilotsequence for the first communication device, so that uplink pilotsequences of all communication devices within the same cell partitionare orthogonal to each other.

Since geographical locations of communication devices within the samecell partition are close to each other the reconfiguration unit 901allocates uplink pilot sequences which are orthogonal to each other forthe communication devices within the same cell partition, to avoidmutual interference between the communication devices. In addition, inorder to further ensure the communication quality, the reconfigurationunit 901 is further configured to reconfigure an uplink pilot sequencefor the first communication device, so that the uplink pilot sequencesof all communication devices within adjacent cells are orthogonal toeach other.

In the example, a pilot pattern may be allocated to each of the cellpartitions in advance as described above. Alternatively, the pilotpattern nay not be allocated to each of the cell partitions in advance,and the reconfiguration unit 901 allocates the pilot pattern randomly asappropriate.

In summary, the apparatus 900 according to the embodiment enables thecommunication devices in the same cell to spatially multiplex the uplinkpilot sequence, thereby supporting more communication devices.

In addition, it should be noted that although the apparatus 900described above includes the channel estimation unit 802 configured toperform the channel estimation operation with the spatial filteringbased on the geographical location, the channel estimation unit 802 isnot necessary. For example, in a case that, the first communicationdevice and the second communication multiplexes the non-orthogonaluplink pilot sequences differed greatly in location, for example, thefirst communication device and the second communication device arelocated at two opposite sides of the cell, respectively, mutualinference between the first communication device and the secondcommunication are not generated even the spatial filtering based on thegeographical location is not performed during the channel estimation. Inother words, in this case, the reconfiguration unit 901 may allocate thenon-orthogonal uplink pilot sequences for the first communication deviceand the second communication device based on their geographical locationrelationship.

In another aspect, although an example of estimating the geographicallocation of the first communication device based on the coarseestimation for the channel coefficients or a measurement result based ona reference signal obtained after beamforming is described in describingthe apparatus 900 described above, the geographical location of thefirst communication device used by the reconfiguration unit 901 can beacquired in other ways.

In other words, an apparatus which enable two or more communicationdevices within a same cell to spatially multiplex the uplink pilotsequence is further provided in the present disclosure, which includes areconfiguration unit 901 configured to reconfigure, based on ageographical location of the first communication device and ageographical location of another communication device to which an uplinkpilot sequence has been allocated, an uplink pilot sequence for thefirst communication device, to enable two or more communication deviceswithin a same cell to multiplex non-orthogonal uplink pilot sequences.The apparatus may preferably include the channel estimation unitdescribed above. However, it should be understood that a way forrealizing the spatial multiplexing is not limited to the specificexample described in the embodiment described above.

The number of user equipments supported can be increased withoutchanging the current pilot sequences by the multiplexing describedabove, thereby improving the utilization efficiency of the pilotsequences.

Similar to the first embodiment, the apparatus 900 may be located ineach access point or on a base station side, and the apparatus 900configures an uplink pilot sequence for a communication device within aservice range of the apparatus 900. The communication device may be auser equipment such as a mobile terminal, a vehicle, an intelligentwearable device and the like. Also, the communication device may also bean infrastructure such as a small cell base station for providingservice.

Correspondingly, FIG. 27 is a flowchart showing a method for wirelesscommunication according to an embodiment of the present disclosure.Besides steps S61 and S62 in FIG. 24, the method further includes stepS72: reconfiguring, based on a geographical location of the firstcommunication device and a geographical location of anothercommunication device to which an uplink pilot sequence has beenallocated, an uplink pilot sequence for the first communication device,to enable two or more communication devices within a same cell tomultiplex non-orthogonal uplink pilot sequences.

In an example, in step S72, the non-orthogonal uplink pilot sequencesare multiplexed by communication devices, locations of which are greatlydifferent from each other. In step S61, a first uplink pilot sequencewhich is orthogonal to an uplink pilot sequence of another communicationdevice to which the uplink pilot sequence has been allocated can bedetermined for the first communication device.

In addition, as shown in a dashed-line block in FIG. 27, the methoddescribed above may further include step S71: dividing a cell intomultiple cell partitions. Specifically, an uplink pilot sequence isreconfigured for the first communication device in step S72, to enableuplink pilot sequences of all communication devices in a same cellpartition to be orthogonal to each other. In an example, an uplink pilotsequence is reconfigured for the first communication device in step S72,to enable uplink pilot sequences of all communication devices withinadjacent cell partitions to be orthogonal to each other.

The signal in the method described above includes an uplink referencesignal, for example, a Sounding Reference Signal (SRS) or a demodulationreference signal (DMRS).

In addition, a method in which an uplink pilot sequence can bemultiplexed spatially by two or more communication devices within a samecell is further provided according to the present disclosure, whichincludes: reconfiguring, based on a geographical location of the firstcommunication device and a geographical location of anothercommunication device to which an uplink pilot sequence has beenallocated, an uplink pilot sequence for the first communication device,to enable two or more communication devices within a same cell tomultiplex non-orthogonal uplink pilot sequences. The method maypreferably include the channel estimation processing based on thespatial filtering described above.

Examples of each step and details thereof may refer to the descriptionin the embodiments described above, which are not repeated here anymore.

The technology of the present disclosure is applicable to variousproducts. For example, the apparatus 400 and 500 may be realized as anytype of server such as a tower server, a rack server, and a bladeserver. The apparatus 400 and 500 may be a control module (such as anintegrated circuit module including a single die, and a card or a bladethat is inserted into a slot of a blade server) mounted on a server.

For example, the apparatus 100-300 and 800 may be realized as any typeof evolved Node B (eNB) such as a macro eNB and a small eNB. The smalleNB may be an eNB such as a pico eNB, a micro eNB, and a home (femto)eNB that covers a cell smaller than a macro cell. Instead, the apparatus100-300 and 800 may be realized as any other types of base stations suchas a NodeB and a base transceiver station (BTS), the apparatus 100-300and 800 may include a main body (that is also referred to as a basestation apparatus) configured to control radio communication, and one ormore remote radio heads (RRH) disposed in a different place from themain body. In addition, various types of terminals, which will bedescribed below, may each operate as the the apparatus 100-300 and 800by temporarily or semi-persistently executing a base station function.

For example, the electronic devices 600 and 700 may be realized as amobile terminal such as a smartphone, a tablet personal computer (PC), anotebook PC, a portable game terminal, a portable/dongle type mobilerouter, and a digital camera, or an in-vehicle terminal such as a carnavigation apparatus, the electronic devices 600 and 700 may also berealized as a terminal (that is also referred to as a machine typecommunication (MTC) terminal) that performs machine-to-machine (M2M)communication. Furthermore, the electronic devices 600 and 700 may be aradio communication module (such as an integrated circuit moduleincluding a single die) mounted on each of the terminals.

The basic principle of the present invention has been described above inconjunction with particular embodiments. However, as can be appreciatedby those ordinarily skilled in the art, all or any of the steps orcomponents of the method and device according to the invention can beimplemented in hardware, firmware, software or a combination thereof inany computing device (including a processor, a storage medium, etc.) ora network of computing devices by those ordinarily skilled in the art inlight of the disclosure of the invention and making use of their generalcircuit designing knowledge or general programming skills.

It can be understood by those skilled in the art that, in the apparatusdescribed above, the location determining unit, the pilot determiningunit, the channel estimation unit, the dividing unit, the pilot patterngenerating unit and so on can be implemented by one or more processor,and the transmitting unit, the receiving unit, the informing interfaceand so on can be implemented by a circuit element such as an antenna, afilter, a modem, a codec and the like.

Therefore, an electronic device (1) is further provided in the presentdisclosure, which includes a circuit configured to: determine a cellpartition corresponding to a geographical location of a communicationdevice, each cell including multiple cell partitions; and determine anuplink pilot sequence corresponding to the cell partition as an uplinkpilot sequence of the communication device.

An electronic device (2) is further provided in the present disclosure,which includes a circuit configured to: divide each of multiple cellsinto multiple cell partitions; and correspond multiple uplink pilotsequences to the multiple cell partitions to generate a pilot pattern,where the pilot pattern is generated based on pilot interferencesbetween different cell partitions which are corresponding to a sameuplink pilot sequence.

An electronic device (3) is further provided in the present disclosure,which includes a circuit configured to: determine, based on indicatinginformation of the uplink pilot sequence allocated by a base station, anuplink pilot sequence of the electronic device; and determine a changein a geographical location of the electronic device, where in a casethat the geographical locations of the electronic device before andafter changing correspond to different cell partitions, the uplink pilotsequence of the electronic device is updated based on the indicatinginformation of the uplink pilot sequence allocated by the base station,and the updated uplink pilot sequence correspond to the cell partitioncorresponding to the geographical location of the electronic deviceafter changing.

An electronic device (4) is further provided in the present disclosure,which includes a circuit configured to: determine a first uplink pilotsequence for a first communication device; and perform, based on areceived signal carrying the first uplink pilot sequence, channelestimation on the first communication device, where filtering isperformed during the channel estimation based on a geographical locationof the first communication device, to obtain a channel estimation resultmatching the first communication device.

Moreover, the present invention further discloses a program product inwhich machine-readable instruction codes are stored. The aforementionedmethods according to the embodiments can be implemented when theinstruction codes are read and executed by a machine.

Accordingly, a memory medium for carrying the program product in whichmachine-readable instruction codes are stored is also covered in thepresent invention. The memory medium includes but is not limited to softdisc, optical disc, magnetic optical disc, memory card, memory stick andthe like.

In the case where the present application is realized by software orfirmware, a program constituting the software is installed in a computerwith a dedicated hardware structure (e.g. the general computer 2800shown in FIG. 28) from a storage medium or network, wherein the computeris capable of implementing various functions when installed with variousprograms.

In FIG. 28, a central processing unit (CPU) 2801 executes variousprocessing according to a program stored in a read-only memory (ROM)2802 or a program loaded to a random access memory (RAM) 2803 from amemory section 2808. The data needed for the various processing of theCPU 2801 may be stored in the RAM 2803 as needed. The CPU 2801, the ROM2802 and the RAM 2803 are linked with each other via a bus 2804. Aninput/output interface 2805 is also linked to the bus 2804.

The following components are linked to the input/output interface 2805:an input section 2806 (including keyboard, mouse and the like), anoutput section 2807 (including displays such as a cathode ray tube(CRT), a liquid crystal display (LCD), a loudspeaker and the like), amemory section 2808 (including hard disc and the like), and acommunication section 2809 (including a network interface card such as aLAN card, modem and the like). The communication section 2809 performscommunication processing via a network such as the Internet. A driver2810 may also be linked to the input/output interface 2805. If needed, aremovable medium 2811, for example, a magnetic disc, an optical disc, amagnetic optical disc, a semiconductor memory and the like, may beinstalled in the driver 2810, so that the computer program readtherefrom is installed in the memory section 2808 as appropriate.

In the case where the foregoing series of processing is achieved thecoarse software, programs forming the software are installed from anetwork such as the Internet or a memory medium such as the removablemedium 2811.

It should be appreciated by those skilled in the art that the memorymedium is not limited to the removable medium 2811 shown in Figure,which has program stored therein and is distributed separately from theapparatus so as to provide the programs to users. The removable medium2811 may be, for example, a magnetic disc (including floppy disc(registered trademark)), a compact disc (including compact discread-only memory (CD-ROM) and digital versatile disc (DVD), a magnetooptical disc (including mini disc (MD)(registered trademark)), and asemiconductor memory. Alternatively, the memory medium may be the harddiscs included in ROM 2802 and the memory section 2808 in which programsare stored, and can be distributed to users along with the device inwhich they are incorporated.

To be further noted, in the apparatus, method and system according tothe invention, the respective components or steps can be decomposedand/or recombined. These decomlocations and/or recombinations shall beregarded as equivalent schemes of the invention. Moreover, the aboveseries of processing steps can naturally be performed temporally in thesequence as described above but will not be limited thereto, and some ofthe steps can be performed in parallel or independently from each other.

Finally, to be further noted, the term “include”, “comprise” or anyvariant thereof is intended to encompass nonexclusive inclusion so thata process, method, article or device including a series of elementsincludes not only those elements but also other elements which have beennot listed definitely or an element(s) inherent to the process, method,article or device. Moreover, the expression “comprising a(n) . . . ” inwhich an element is defined will not preclude presence of an additionalidentical element(s) in a process, method, article or device comprisingthe defined element(s)” unless further defined.

Although the embodiments of the invention have been described above indetail in connection with the drawings, it shall be appreciated that theembodiments as described above are merely illustrative but notlimitative of the invention. Those skilled in the art can make variousmodifications and variations to the above embodiments without departingfrom the spirit and scope of the invention. Therefore, the scope of theinvention is defined merely by the appended claims and theirequivalents.

1. An apparatus for wireless communication, comprising: a locationdetermining unit, configured to determine a cell partition correspondingto a geographical location of a communication device, wherein each cellcomprises a plurality of cell partitions; and a pilot determining unit,configured to determine an uplink pilot sequence corresponding to thecell partition as an uplink pilot sequence of the communication device.